locked
External USB drives slowing me down? RRS feed

  • Question

  • Hi all, When I first set up my server I had two internal 500Gb SATA II drives, 2.66 P4, 1 Gb memory and it is running the latest Beta version. I have a client machine running MCE 2005 and the add on program My Movies to catalogue my DVD collection. I put 750 Gb of movies on the server and all was going well until I decided to add three external 500Gb Western Digital My Book USB drives to the server. Now when I watch a movie on the MCE machine, it starts out great but two or three times during the movie it freezes like it is trying to find the next part of the movie. After two or three minutes it starts back up and all is fine until the next freeze. I do not have duplication on at this point.

     

    My question is, are the USB drives so much slower than the SATA II drives that it causes this delay or could it be that the movies are so spread out on the five drives from balancing that the server has a hard time finding it quickly?  When the retail release comes out, and I rebuild my server, if I need to quit using the externals I can, it just seems as though they should be more than capable.

     

    I periodically get drive failure warnings on the external drives but the repair function or a reboot brings everything back to a healthy state. Thanks for your input.

     

     

    Sunday, September 30, 2007 12:58 AM

Answers

  • You can't disable the spindown on WD Mybook drives that have that feature. WD says so right here.

    As for USB PCI cards, you can check Device Manager to see how many hubs the card supplies, but my experience has been that they supply one hub, no matter how many USB ports they have. If all of your drives are on the PCI card, then you're sharing your (probably) 25-or-so MB/s among 4 drives.
    Sunday, September 30, 2007 4:42 PM
    Moderator

All replies

  • Things to consider:
    • Real world throughput on USB 2.0 maxes out at about 30 MB/s. Theoretical maximum is about 45 MB/s, but the way USB works means you'll never get close to that. (You can get pretty close to 100% with Firewire, by the way.)
    • Since a given file is going to be stored entirely on a single drive, there's no problem with WHS needing to figure out where the next piece of the file is, and the available bandwidth should be more than adequate.
    • External USB drives may cause performance issues if you have multiple drives connected to a single USB hub, however, because the bandwidth on that hub is shared among all devices on the hub.
    • Your network is probably going to have less real bandwidth than a USB 2.0 drive. Typical speeds I see for gigabit Ethernet in home environments is around 20-25 MB/s, well below the theoretical 100 MB/s that it should be capable of.
    If your external drives are throwing occasional errors as you say, it's possible that they are failing. It's also possible that some power saving feature is causing them to go into a reduced power state which is looking like an error. If you can, I'd consider running a disk diagnostic on the external drives, and configuring them to turn off all power-saving features.
    Sunday, September 30, 2007 2:30 AM
    Moderator
  • Thanks for your input. When you say hub, would a PCI USB card fall into that? I installed a 4 port card so that I wasn't going through any external hubs. I'll have to see about running the diagnostic on the drives, they are all brand new so I doubt that they are all failing. The software that was installed on them did have power saving features but, I believe I wiped all that out by reformatting them with WHS. I wasn't aware as you said "a given file is stored entirely on a single drive", that takes care of that idea. It would seem that if my goal is a stable and reliable media server, when I build my final version, going with internal SATA II drives is probably the way to go. One last question, would external SATA drives function well for this use?

    Sunday, September 30, 2007 2:37 PM
  • Hi blamarsh,

     

    I'm basically agreeing with what Ken said, with two little extras.

     

    1. I've got a couple of WD My Books, and they do have power saving features built-in, which have caused me problems from time to time when using the USB ports.

     

    2. Seems you have a MCE machine, you maybe aware that some USB tuners have problems with certain USB chipsets not beening able to cope with the speed/amount of data. I've seen it recomend that you should use PCI cards by Belkin or with NEC chipsets with these tuners, as your problem appears to be with big movie files, this could be some thing similar.

    Sunday, September 30, 2007 2:50 PM
  • S-Puppy, I believe the WHS reformat of the USB drives should have removed the power saving features, though I am no expert. The client machine is a  H-P Digital Entertainment unit with built in tuners running in the living room, while the movies are stored on the server in the basement. When you refer to USB tuners are you talking about TV tuners or does that have something to do with the hardware on a USB PCI card with external ports? Are you thinking that the PCI card that the WD My Books are hooked up to might be at fault?

    Sunday, September 30, 2007 3:25 PM
  • You can't disable the spindown on WD Mybook drives that have that feature. WD says so right here.

    As for USB PCI cards, you can check Device Manager to see how many hubs the card supplies, but my experience has been that they supply one hub, no matter how many USB ports they have. If all of your drives are on the PCI card, then you're sharing your (probably) 25-or-so MB/s among 4 drives.
    Sunday, September 30, 2007 4:42 PM
    Moderator
  • Blamarh,

    The power saving features aren't on the actual drive, they will be in the firmware and you would have to use the drive manufacturers program to set/unset it.

    All USB ports on one PCI card will share the throughput, as it will be one hub. You would be better having one drive on the internal builtin hub and one on the PCI card.

     

    Colin

     

    Sunday, September 30, 2007 4:52 PM
  • Thank you all for the responses, I believe you are correct pointing to all the external drives being plugged into the one card slowing me down. What option do you have with multiple USB drives, a seperate card for each? Also, would this same theory hold true for ESATA drives/

    Sunday, September 30, 2007 6:42 PM
  •  

    Hi blamarsh,

     

    Yes, it was TV tuners I ment, the Hauppauge USB2.0 to be exact. 

    After reading Ken's post I think I remember why the Belkin / NEC PCI cards were best. I believe some of them use two chips or hubs for each card, hence you could use 2x USB tuners on them.

     

    Also as Ken said, you can't turn off the 'Power Saving' on the My Books, which is a pain as sometimes they only seem to 'half' wake up. Meaning you've got to remove and add them again to get full speed transfers. 

     

    SATA drives whether internal or external should be fine as they are the only drive on that channel.

     

     

    ColinWH,

     

    Do you know away of turning off the power saving on the My Books ?

    Sunday, September 30, 2007 10:09 PM
  • Evening,

    From the little work I've done on the MyBook range, I think the power saving mode is part of the controller firmware, as installing a new disk in the housing inherits the same 10 minute power-down.

     

    Colin

    Monday, October 1, 2007 5:31 PM
  • Thanks for the response, it seems like this could be a cause of part of my problems. If these drives power-down after 10 minutes of inactivity, when I'm watching a movie, wouldn't that constitute activity? All of the movies start o'k they just freeze up a few times during the movie, I'll have to time the freeze points and see if there is any pattern. They do not freeze every ten minutes, more like every 20-30 minutes.

    Tuesday, October 2, 2007 12:56 AM